fix(api): Retry API requests on DNS resolution failure

When DNS resolution fails (CURLE_COULDNT_RESOLVE_HOST), the CLI now
retries the request using the existing exponential backoff retry
mechanism. This addresses intermittent DNS failures that were causing
~5-10% of builds to fail.

Fixes #2763

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: szokeasaurusrex

src/api/errors/mod.rs

@@ -28,3 +28,20 @@ impl RetryError {
         self.body
     }
 }
+
+#[derive(Debug, thiserror::Error)]
+#[error("request failed with retryable curl error: {source}")]
+pub(super) struct RetryableCurlError {
+    #[source]
+    source: curl::Error,
+}
+
+impl RetryableCurlError {
+    pub fn new(source: curl::Error) -> Self {
+        Self { source }
+    }
+
+    pub fn into_source(self) -> curl::Error {
+        self.source
+    }
+}

src/api/mod.rs

@@ -15,6 +15,7 @@ mod serialization;
 use std::borrow::Cow;
 use std::cell::RefCell;
 use std::collections::HashMap;
+use std::error::Error as StdError;
 #[cfg(any(target_os = "macos", not(feature = "managed")))]
 use std::fs::File;
 use std::io::{self, Read as _, Write};
@@ -41,7 +42,7 @@ use symbolic::common::DebugId;
 use symbolic::debuginfo::ObjectKind;
 use uuid::Uuid;
 
-use crate::api::errors::{ProjectRenamedError, RetryError};
+use crate::api::errors::{ProjectRenamedError, RetryError, RetryableCurlError};
 use crate::config::{Auth, Config};
 use crate::constants::{ARCH, EXT, PLATFORM, RELEASE_REGISTRY_LATEST_URL, VERSION};
 use crate::utils::http::{self, is_absolute_url};
@@ -1313,7 +1314,20 @@ impl ApiRequest {
             debug!("retry number {retry_number}, max retries: {max_retries}");
             *retry_number += 1;
 
-            let mut rv = self.send_into(&mut out)?;
+            let result = self.send_into(&mut out);
+
+            // Check for retriable curl errors (DNS resolution failure)
+            if let Err(ref api_err) = result {
+                if let Some(source) = api_err.source() {
+                    if let Some(curl_err) = source.downcast_ref::<curl::Error>() {
+                        if curl_err.is_couldnt_resolve_host() {
+                            anyhow::bail!(RetryableCurlError::new(curl_err.clone()));
+                        }
+                    }
+                }
+            }
+
+            let mut rv = result?;
             rv.body = Some(out);
 
             if RETRY_STATUS_CODES.contains(&rv.status) {
@@ -1326,7 +1340,7 @@ impl ApiRequest {
         send_req
             .retry(backoff)
             .sleep(thread::sleep)
-            .when(|e| e.is::<RetryError>())
+            .when(|e| e.is::<RetryError>() || e.is::<RetryableCurlError>())
             .notify(|e, dur| {
                 debug!(
                     "retry number {} failed due to {e:#}, retrying again in {} ms",
@@ -1337,7 +1351,10 @@ impl ApiRequest {
             .call()
             .or_else(|err| match err.downcast::<RetryError>() {
                 Ok(err) => Ok(err.into_body()),
-                Err(err) => Err(ApiError::with_source(ApiErrorKind::RequestFailed, err)),
+                Err(err) => match err.downcast::<RetryableCurlError>() {
+                    Ok(curl_err) => Err(ApiError::from(curl_err.into_source())),
+                    Err(err) => Err(ApiError::with_source(ApiErrorKind::RequestFailed, err)),
+                },
             })
     }
 }